Some background on the motivation for my question:
I am the developer of IguanaTex, a PowerPoint add-in to insert LaTeX displays/equations into PowerPoint.
Many Mac users use another software, LatexIt, to insert PDF generated from LaTeX into PowerPoint; the PDF stores the LaTeX source as metadata (in a rather complex way), and this metadata is still accessible in the EMF file that PowerPoint uses internally to store the PDF (which can be obtained by unzipping the .pptx file). It is also preserved in a PDF created by using "Save as PDF" on the Mac.
I would like to allow IguanaTex users on Windows to retrieve that LaTeX information so that they can modify slides created by LatexIt users on the Mac.

My problem:
I thought I could extract the internal EMF with "Save as .emf", and parse it. LatexIt's developer kindly prepared a Windows executable that can retrieve that information from an EMF file such as the one stored internally by PowerPoint.
Unfortunately, I realized that using "Save as .emf" on Windows to get an EMF file from the picture obtained by inserting a PDF on Mac did not lead to the same EMF file that PowerPoint uses internally, and the LatexIt metadata is lost in the process.
I am pessimistic, but does anyone see a way around this? Either to get access to the internal EMF file somehow, or save as EMF using some other procedure?

Thanks,
Jonathan